周书林 via llvm-dev
2021-Jun-11 01:01 UTC
[llvm-dev] What is relationship between Operator and Instruction?
Hi Rahul, Thank you very much! Sincerely, Shulin rahul utkoor <rahulutkoor4887 at gmail.com> 于2021年6月10日周四 下午9:21写道：> Hi, > > LLVM modularity provides developers a unique opportunity to come up with > better design decisions on individual components. Your questions related to > "*Operators and ConstantExprs*", I suggest you spend some time, and > understand the passes that are responsible for generating those > instructions. > As the code base is really huge and many smart people from different parts > of the world are contributing to this project, there might be some things > that can get missed in LangRef. In such a case, many times I used gdb/lldb > debugger tools for understanding the pipeline. > > Use debugging tools and identify the logic that is responsible for > generating instructions(*Operators and ConstantExprs*). I am giving you > directions to get started with understanding LLVM internals. > > > Thanks, > Rahul Utkoor > > On Thu, Jun 10, 2021 at 4:59 PM jeniffer lesley <jenifferlesley7 at gmail.com> > wrote: > >> I second this question. I never undersrood this in LLVM IR. LangRef fails >> to explain this. >> >> On Thu, Jun 10, 2021, 4:46 PM 周书林 via llvm-dev <llvm-dev at lists.llvm.org> >> wrote: >> >>> Hi, >>> >>> Thank you for your suggestions. >>> I have learnt the basic IR structures in simple programs, but not all >>> the objects could be generated. As I mentioned, about the Operators and >>> ConstantExprs. I only got GEPOperator objects from .bc of MySQL. So is >>> there any reference to learn about the relationship between those classes >>> in IR? >>> >>> Sincerely, >>> Shulin >>> >>> rahul utkoor <rahulutkoor4887 at gmail.com> 于2021年6月10日周四 下午5:25写道： >>> >>>> Hello, >>>> Since you are starting to learn IR, I recommend you to start with one >>>> simple program, compile the program, genreate CFG and understand the >>>> hierarchy of types/operands/instructions. >>>> It helped me to understand the compilation pipeline in a quick way. >>>> >>>> >>>> Thanks, >>>> Rahul Utkoor >>>> >>>> >>>> On Thu, 10 Jun, 2021, 2:08 pm 周书林 via llvm-dev, < >>>> llvm-dev at lists.llvm.org> wrote: >>>> >>>>> Hello everyone, >>>>> >>>>> I am learning the IR in LLVM and trying to do some analysis. Now I am >>>>> doing a dataflow analysis via the def-use chain provided by Users. >>>>> >>>>> In my opinion, the Users of a Value should be an instruction. However, >>>>> when I iterate the User of a Value, sometimes I get an Operator, like >>>>> GEPOperator, or an ConstantExpr. >>>>> I am quite confused about these situations. My question is, what is >>>>> Operator in IR? and what is the difference between Operator and >>>>> Instruction? Why can I get a GEPOperator as an Operand in a instruction >>>>> rather than two instruction( a gep instruction and the next User >>>>> instruction) ? >>>>> >>>>> Best regards, >>>>> Shulin >>>>> _______________________________________________ >>>>> LLVM Developers mailing list >>>>> llvm-dev at lists.llvm.org >>>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >>>>> >>>> _______________________________________________ >>> LLVM Developers mailing list >>> llvm-dev at lists.llvm.org >>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >>> >>-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20210611/eae0ec46/attachment.html>